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. Author manuscript; available in PMC: 2024 Jul 12.
Published in final edited form as: Obs Stud. 2023;9(4):25–48. doi: 10.1353/obs.2023.a906627

Table 1:

Estimated power from the proposed power calculations using a pilot study of size n0 for varying sample sizes n. We assume the effect size under the alternative hypothesis is given by η=1.4.Δ denotes the difference between the true value of the optimal regime and B0 which is given by η(1+Δ), so Δ=0 corresponds to the true effect size being equal to η. The remaining columns display the mean, median, and standard deviation of the estimated powers across 500 simulated pilot studies as well as the true power which is calculated via simulation. We do not estimate the power for n=250 when the pilot is of size n0=400, since it is implausible for the pilot sample size to exceed the full study sample size.

Δ n n0 True PWR Mean PWR Med PWR SD PWR

0 250 200 0.42 0.54 0.54 0.32
0.25 250 200 0.99 0.96 0.99 0.09
0.5 250 200 1.00 1.00 1.00 0.01

0 500 200 0.83 0.77 0.92 0.30
0.25 500 200 1.00 0.99 1.00 0.04
0.5 500 200 1.00 1.00 1.00 0.00

0 750 200 0.98 0.84 0.99 0.27
0.25 750 200 1.00 1.00 1.00 0.02
0.5 750 200 1.00 1.00 1.00 0.00

0 500 400 0.82 0.77 0.85 0.24
0.25 500 400 1.00 1.00 1.00 0.01
0.5 500 400 1.00 1.00 1.00 0.00

0 750 400 0.98 0.89 0.98 0.19
0.25 750 400 1.00 1.00 1.00 0.00
0.5 750 400 1.00 1.00 1.00 0.00